Label-Free Biochemical Sensors Based on Optical Microresonators

Biochemical sensors play a significant role in extensive applications that have tight relationship with human life. These sensors require high sensitivity and low detection limit. In this chapter, two optical sensors that meet the requirement will be discussed: polymer microring biochemical sensors and microtube resonator sensors. Both have advantages of high sensitivity, label-free detection capability, low cost, robustness, and simple fabrication process. The former devices show high sensitivity over 70 nm per RIU and low detection limit as 250 pg mm−2, while the latter ones can push sensitivity to 600 nm per RIU. Moreover, polymer microring biochemical sensors are compact and integrable in an array on a substrate; while microtube-based sensors have built-in fluidic handling capability. These features facilitate the development of miniature and highly sensitive lab-on-a-chip sensors.